KR102674885B1 - Apparatus for operating in-wheel motor of in-wheel system and control method thereof - Google Patents

Abstract

The present invention discloses an in-wheel motor driving device for an in-wheel system and a control method thereof. The in-wheel motor driving device of the in-wheel system of the present invention includes a motor signal input unit that receives the resolver signal of each in-wheel motor as a motor signal; A vehicle signal input unit that receives a wheel speed signal from a wheel speed sensor that measures the wheel speed at each wheel as a vehicle signal; A steering angle detection unit for detecting the steering angle; An in-wheel motor driving unit that drives each in-wheel motor; And the driving state is determined according to the steering angle input from the steering angle detection unit, and in case of turning, the main difference between the motor signal and the vehicle signal at each wheel is calculated and compared, and the in-wheel escape speed is adjusted according to the comparison result to control the in-wheel motor drive unit. It is characterized in that it includes a control unit that controls.

Description

In-wheel motor driving device of in-wheel system and its control method {APPARATUS FOR OPERATING IN-WHEEL MOTOR OF IN-WHEEL SYSTEM AND CONTROL METHOD THEREOF}

The present invention relates to an in-wheel motor driving device of an in-wheel system and a control method thereof. More specifically, in a vehicle equipped with an in-wheel system, the resolver signal of the in-wheel motor mounted on each wheel is compared with the wheel speed at each wheel. This relates to an in-wheel motor driving device and a control method for an in-wheel system that can prevent oversteer by determining an inverter control abnormality in a straight section, estimating the lateral acceleration in a turning section, and driving the in-wheel motor. .

In general, the Autonomous Emergency Braking System (AEBS) is a system that can minimize damage from collisions by performing warning and automatic braking functions when a collision with a vehicle located in front of the control vehicle is visible.

Here, AEBS monitors the relative distance to the vehicle in front and the presence or absence of the vehicle ahead to determine when AEB control will be activated and released. Front vehicle monitoring sensors currently in use include radar, lidar, and cameras.

At this time, the sensor module for monitoring the vehicle ahead is mounted on the upper part of the windshield in the case of camera/lidar, and on the upper and lower grille of the vehicle in the case of radar.

In addition, in recent years, in response to the severity of environmental problems caused by the use of fossil fuels such as gasoline and diesel fuel and the depletion of limited resources, electric vehicles, fuel cell vehicles, hybrid vehicles, etc. driven by motors have been developed.

The in-wheel system is a system in which an in-wheel motor is mounted inside the wheel of each wheel of the vehicle and each wheel can be controlled by independent drive. The drive system is simple and space utilization is excellent.

In addition, each wheel can be controlled by independent driving, allowing torque for each wheel to be adjusted, thereby improving the vehicle's driving performance.

The background technology of the present invention is disclosed in Republic of Korea Patent Publication No. 10-1526622 (2015.06.08 notice, Method for preventing engine stop when operating automatic emergency braking system).

When a vehicle turns, not only does lateral acceleration due to centrifugal force occur, but the driving force load transfers from the inside to the outside, and the rigidity of the surrounding parts, including the wheel bearings or suspension of the suspension, also changes.

Therefore, if the centrifugal force generated when turning the vehicle exceeds the maximum driving force, oversteer, which is an uncontrollable state of the vehicle, may occur, causing lane departure or, in the worst case, overturning.

However, in the past, there was a problem in determining the driving state of the vehicle based on vehicle signals or reflecting signal errors due to changes in rigidity of tires, suspension, and in-wheel drive devices that occur when the vehicle turns in vehicle performance control.

The present invention was made to improve the problems described above, and the purpose of the present invention according to one aspect is to determine the resolver signal of the in-wheel motor mounted on each wheel and the wheel speed at each wheel in a vehicle equipped with an in-wheel system. By comparing, the in-wheel motor driving device and its control method of the in-wheel system that can prevent oversteer by determining abnormalities in inverter control in the straight section and estimating the lateral acceleration in the turning section to drive the in-wheel motor. It is provided.

An in-wheel motor driving device of an in-wheel system according to an aspect of the present invention includes a motor signal input unit that receives the resolver signal of each in-wheel motor as a motor signal; A vehicle signal input unit that receives a wheel speed signal from a wheel speed sensor that measures the wheel speed at each wheel as a vehicle signal; A steering angle detection unit for detecting the steering angle; An in-wheel motor driving unit that drives each in-wheel motor; And the driving state is determined according to the steering angle input from the steering angle detection unit, and in case of turning, the main difference between the motor signal and the vehicle signal at each wheel is calculated and compared, and the in-wheel escape speed is adjusted according to the comparison result to control the in-wheel motor drive unit. It is characterized in that it includes a control unit that controls.

In the present invention, the control unit determines the driving state and outputs a warning when the main difference between the motor signal and the vehicle signal at each wheel continues for a second set time longer than the first set value in the case of straight driving.

In the present invention, the control unit compares the main differential between each wheel and increases the in-wheel escape speed if it is less than a second set value, and reduces the in-wheel escape speed if it is determined that oversteer is likely to occur if it is more than the second set value. do.

In the present invention, the second setting value is set differently depending on the speed of the vehicle.

In the present invention, the control unit calculates the main difference between the motor signal at each wheel and the vehicle signal by applying an error correction value or weight according to the vehicle state.

The present invention further includes a warning unit that outputs a warning according to the operating state of the control unit.

In the control method of the in-wheel motor driving device of the in-wheel system according to another aspect of the present invention, the control unit receives a resolver signal as a motor signal from the motor signal input unit, receives a wheel speed signal as a vehicle signal from the vehicle signal input unit, and receives the steering angle. Receiving a steering angle from a sensing unit; A step where the control unit determines the driving state based on the steering angle; After the control unit determines the driving state, in case of turning driving, calculating the main difference between the motor signal and the vehicle signal at each wheel and comparing them between each wheel; And the control unit controls the in-wheel motor driving unit by adjusting the in-wheel escape speed based on the main vehicle compared between each wheel.

The present invention further includes the step of outputting a warning when the main difference between the motor signal and the vehicle signal at each wheel continues for a second set time longer than the first set value when driving straight after the control unit determines the driving state. Do it as

The present invention is characterized in that when calculating the main difference between the motor signal at each wheel and the vehicle signal, the error correction value or weight is applied according to the vehicle state.

In the present invention, the step of controlling the in-wheel motor driving unit by adjusting the in-wheel escape speed includes the control unit comparing the main differential between each wheel and the second set value, and if the difference is less than the second set value, the control unit increases the in-wheel escape speed to control the in-wheel motor driving unit. controlling; A step where the control unit compares the main difference between each wheel and a second set value and, if the difference is more than the second set value, determines whether oversteer may occur; and a step of controlling the in-wheel motor driving unit by reducing the in-wheel escape speed when the control unit determines that oversteer is likely to occur.

In the present invention, the control unit determines that oversteer may occur, and if it is not determined that oversteer may occur, the control unit increases the in-wheel de-axle speed to control the in-wheel motor driving unit.

In the present invention, the second setting value is set differently depending on the speed of the vehicle.

The in-wheel motor driving device of the in-wheel system and its control method according to an aspect of the present invention compare the resolver signal of the in-wheel motor mounted on each wheel and the wheel speed at each wheel in a vehicle equipped with the in-wheel system, By determining an inverter control abnormality, estimating the lateral acceleration in the turning section, and driving the in-wheel motor, oversteer can be prevented without a separate lateral acceleration sensor.

1 is a block diagram showing an in-wheel motor driving device of an in-wheel system according to an embodiment of the present invention.
Figure 2 is a graph comparing motor signals and vehicle signals in the in-wheel motor driving device of the in-wheel system according to an embodiment of the present invention.
Figure 3 is a flowchart for explaining a control method of an in-wheel motor driving device of an in-wheel system according to an embodiment of the present invention.

Hereinafter, an in-wheel motor driving device and a control method thereof of an in-wheel system according to the present invention will be described with reference to the attached drawings. In this process, the thickness of lines or sizes of components shown in the drawing may be exaggerated for clarity and convenience of explanation. In addition, the terms described below are terms defined in consideration of functions in the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, definitions of these terms should be made based on the content throughout this specification.

Figure 1 is a block diagram showing an in-wheel motor driving device of an in-wheel system according to an embodiment of the present invention, and Figure 2 is a block diagram showing a motor signal and a vehicle signal in an in-wheel motor driving device of an in-wheel system according to an embodiment of the present invention. This is a comparison graph.

As shown in FIG. 1, the in-wheel motor driving device of the in-wheel system according to an embodiment of the present invention includes a motor signal input unit 10, a vehicle signal input unit 20, a steering angle detection unit 30, and an in-wheel motor driving unit 50. ) and a control unit 40, as well as a warning unit 70.

The motor signal input unit 10 may receive a resolver signal indicating the rotor position of each in-wheel motor 60 as a motor signal and provide the resolver signal to the control unit 40.

Here, the resolver signal may represent a motor signal that is not affected by changes in rigidity due to the lateral force of the vehicle.

The vehicle signal input unit 20 may receive a wheel speed signal from a wheel speed sensor (not shown) that measures the wheel speed at each wheel as a vehicle signal and provide the wheel speed signal to the control unit 40.

When a vehicle drives, the load acting on the wheels can be divided into those caused by the road surface condition and those caused by the driving movement of the vehicle.

In addition, the change in wheel load during straight driving is mainly due to the vertical component, and the lateral (lateral) direction load that acts harshly on the wheel hub is relatively minor. However, in a turning state, not only the vertical load but also the lateral (lateral) direction load, which causes severe damage to the wheel and hub, is generated at the same time. Therefore, when the vehicle turns, the lateral load causes changes in the stiffness of tires, suspension, and in-wheel systems.

Here, the wheel speed signal at each wheel shows a change in stiffness in the in-wheel system and suspension due to the influence of lateral force when turning, and the change in stiffness can appear as the amount of displacement of surrounding parts. In other words, in the case of wheel bearings, the period of the wheel speed signal may increase or decrease compared to straight driving due to the influence of rigidity displacement.

The steering angle detection unit 30 can detect the steering angle at which the steering wheel is rotated and provide the information to the control unit 40.

The in-wheel motor driving unit 50 can drive the in-wheel motor 60 by applying a three-phase driving current to the in-wheel motor 60 through an inverter.

The control unit 40 determines the driving state according to the steering angle input from the steering angle detection unit 30, and in case of turning driving, for example, when the steering angle exceeds 5 degrees and is maintained for more than 3 seconds, the motor signal from each wheel and The in-wheel motor 60 can be driven by calculating and comparing the main difference between vehicle signals and controlling the in-wheel motor driving unit 50 by adjusting the in-wheel escape speed according to the comparison result.

As shown in Figure 2, when comparing the motor signal and the vehicle signal, the motor signal (a, b) is constant because there is no change in stiffness due to external force. On the other hand, the camber angle of the vehicle signal (c) changes due to a change in rigidity due to the lateral load when the vehicle turns, and this causes the vehicle signal to change, so the lateral acceleration can be estimated based on the main difference between the motor signal and the vehicle signal. there is.

Here, when calculating the main difference between the motor signal from each wheel and the vehicle signal, the control unit 40 generates an error according to the vehicle's running speed, load, center of gravity, vehicle front/rear distribution status, etc. input through the vehicle status input unit 80. The periodic difference can also be calculated by applying correction values or weights.

In this way, after calculating the main difference between the motor signal and the vehicle signal, the main difference between each wheel is compared. If it is less than the second set value of 3 ms, the in-wheel escape speed is increased, and if it is more than the second set value, oversteer occurs by more than 5 ms. If the possibility is determined, the in-wheel escape speed can be reduced.

Here, 3ms is a value set when the vehicle speed is 50 kph, and the second set value can be set differently depending on the vehicle speed.

In addition, the control unit 40 determines the driving state, and when driving straight with a steering angle of 5 degrees or less, the periodic difference between the motor signal at each wheel and the vehicle signal is greater than the first set value of 5 ms, and the second set time of 5 seconds is set. If it continues, a warning can be output to encourage the vehicle to stop.

On the other hand, if the duration does not last for 5 seconds, a warning can be issued by determining the control status of the inverter.

The warning unit 70 can output a warning depending on the operating state of the control unit 40 to induce stopping or inspection of the vehicle.

As described above, according to the in-wheel motor driving device of the in-wheel system according to the embodiment of the present invention, the resolver signal of the in-wheel motor mounted on each wheel in a vehicle equipped with the in-wheel system is compared with the wheel speed at each wheel. By determining an inverter control abnormality in the straight section, estimating the lateral acceleration in the turning section, and driving the in-wheel motor, oversteer can be prevented without a separate lateral acceleration sensor.

Figure 3 is a flowchart for explaining a control method of an in-wheel motor driving device of an in-wheel system according to an embodiment of the present invention.

As shown in FIG. 3, in the control method of the in-wheel motor driving device of the in-wheel system according to an embodiment of the present invention, first, the control unit 40 receives a resolver signal as a motor signal from the motor signal input unit 10, A wheel speed signal is received as a vehicle signal from the vehicle signal input unit 20, and a steering angle is received from the steering angle detection unit 30 (S10).

Here, the control unit 40 can receive a resolver signal indicating the rotor position of each in-wheel motor 60 as a motor signal, and a wheel speed sensor (not shown) that measures the wheel speed at each wheel as a vehicle signal. Wheel speed signals can be input.

After receiving the steering angle in step S10, the control unit 40 determines the driving state based on the steering angle (S12). In other words, it is determined whether it is straight driving or turning driving.

At this time, the control unit 40 can determine whether straight driving or turning driving by determining whether the steering angle exceeds 5 degrees and is maintained for more than 3 seconds.

If the driving state is determined in step S12 and the driving condition is turning, the control unit 40 calculates the main difference between the motor signal and the vehicle signal at each wheel (S20).

Here, when calculating the main difference between the motor signal at each wheel and the vehicle signal, the control unit 40 generates an error according to the vehicle's driving speed, load, center of gravity, vehicle front/rear distribution status, etc. input through the vehicle status input unit 80. The periodic difference can also be calculated by applying correction values or weights.

After calculating the main difference between the motor signal and the vehicle signal at each wheel in step S20, the control unit 40 compares the main difference between each wheel (S22).

After comparing the main difference between each wheel in step S22, the control unit 40 determines whether the main difference is greater than the second set value (S24).

Here, the second setting value can be set differently depending on the speed of the vehicle. For example, when the vehicle speed is 50kph, it can be set to 3ms.

In step S24, after determining whether the main vehicle differs by more than the second set value, if the difference is less than the second set value, the control unit 40 increases the in-wheel escape speed and controls the in-wheel motor driving unit 50 to operate the in-wheel motor 60. Drive it (S30).

In step S24, after determining whether the main differential differs by more than the second set value, the control unit 40 determines the possibility of oversteer occurring (S26).

Here, the possibility of oversteer occurring can be determined as the possibility of oversteer occurring when the main difference between each wheel occurs by more than 5 ms.

In step S26, if the possibility of oversteer occurring is determined and there is no possibility, the control unit 40 increases the in-wheel escape speed and controls the in-wheel motor driving unit 50 to drive the in-wheel motor 60 (S30).

On the other hand, in step S26, the possibility of oversteer is determined, and if it is possible, the control unit 40 reduces the in-wheel escape speed and controls the in-wheel motor driving unit 50 to drive the in-wheel motor 60 (S28).

Meanwhile, if the driving state is determined in step S12 and the driving condition is straight driving, the control unit 40 determines whether a main difference occurs between the motor signal and the vehicle signal at each wheel (S14).

Here, in the case of straight driving, the change in wheel load is mainly in the vertical direction, and the lateral (lateral) direction load that acts harshly on the wheel hub is minimal.

Accordingly, the control unit 40 can determine whether the periodic difference between the motor signal and the vehicle signal at each wheel is greater than or equal to the first set value of 5 ms.

If there is a difference of more than 5 ms in the main difference between the motor signal and the vehicle signal at each wheel in step S14, the control unit 40 determines whether the main difference continues for more than 5 seconds, which is the second set time (S16).

If it continues for more than the second set time in step S16, the control unit 40 outputs a warning through the warning unit 70 so that the vehicle can be stopped and confirmed (S18).

On the other hand, if the duration does not last for 5 seconds, a warning can be issued by determining the control status of the inverter.

As described above, according to the control method of the in-wheel motor driving device of the in-wheel system according to the embodiment of the present invention, the resolver signal of the in-wheel motor mounted on each wheel in the vehicle equipped with the in-wheel system and the wheel vehicle speed at each wheel By comparing the inverter control abnormalities in the straight section and estimating the lateral acceleration in the turning section to drive the in-wheel motor, over steer can be prevented without a separate lateral acceleration sensor.

Implementations described herein may be implemented, for example, as a method or process, device, software program, data stream, or signal. Although discussed only in the context of a single form of implementation (eg, only as a method), implementations of the features discussed may also be implemented in other forms (eg, devices or programs). The device may be implemented with appropriate hardware, software, firmware, etc. The method may be implemented in a device such as a processor, which generally refers to a processing device that includes a computer, microprocessor, integrated circuit, or programmable logic device. Processors also include communication devices such as computers, cell phones, portable/personal digital assistants (“PDAs”) and other devices that facilitate communication of information between end-users.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely exemplary, and those skilled in the art will recognize that various modifications and other equivalent embodiments are possible therefrom. You will understand.

Therefore, the true technical protection scope of the present invention should be determined by the claims below.

10: motor signal input unit 20: vehicle signal input unit
30: Steering angle detection unit 40: Control unit
50: In-wheel motor driving unit 60: In-wheel motor
70: warning unit 80: vehicle status input unit

Claims (12)

A motor signal input unit that receives the resolver signal of each in-wheel motor as a motor signal;
A vehicle signal input unit that receives a wheel speed signal from a wheel speed sensor that measures the wheel speed at each wheel as a vehicle signal;
A steering angle detection unit for detecting the steering angle;
an in-wheel motor driving unit that drives each of the in-wheel motors; and
The driving state is determined according to the steering angle input from the steering angle detection unit, and in case of turning driving, the periodic difference between the motor signal and the vehicle signal at each wheel is calculated and compared, and the in-wheel escape speed is determined according to the comparison result. An in-wheel motor driving device of an in-wheel system, comprising: a control unit that adjusts and controls the in-wheel motor driving unit.
The method of claim 1, wherein the control unit determines the driving state and, in case of straight driving, issues a warning when the main difference between the motor signal and the vehicle signal at each wheel exceeds the first set value and continues for a second set time. An in-wheel motor driving device of an in-wheel system characterized by output.
The method of claim 1, wherein the control unit compares the main differential between each wheel to increase the in-wheel escape speed if it is less than a second set value, and if it is determined that oversteer is likely to occur if it is more than the second set value, the in-wheel escape speed is adjusted. An in-wheel motor driving device of an in-wheel system characterized by reducing escape speed.
The in-wheel motor driving device of claim 3, wherein the second set value is set differently depending on the speed of the vehicle.
The in-wheel system according to claim 1, wherein the control unit calculates the main difference between the motor signal and the vehicle signal at each wheel by applying an error correction value or weight according to the vehicle state. motor drive device.
The in-wheel motor driving device of claim 1, further comprising a warning unit that outputs a warning according to the operating state of the control unit.
A step where the control unit receives a resolver signal as a motor signal from a motor signal input unit, receives a wheel speed signal as a vehicle signal from a vehicle signal input unit, and receives a steering angle from a steering angle detection unit;
The control unit determining a driving state based on the steering angle;
After the control unit determines the driving state, when turning driving is performed, calculating a periodic difference between the motor signal and the vehicle signal at each wheel and comparing them between each wheel; and
A method of controlling an in-wheel motor driving device of an in-wheel system, comprising: the control unit controlling an in-wheel motor driving unit by adjusting an in-wheel escape speed based on the main vehicle compared between each wheel.
The method of claim 7, wherein in case of straight driving after the control unit determines the driving state, a warning is output when the main difference between the motor signal and the vehicle signal at each wheel exceeds the first set value and continues for the second set time. A method of controlling an in-wheel motor driving device of an in-wheel system, further comprising the step of:
The in-wheel motor driving device of claim 7, wherein when calculating the main difference between the motor signal and the vehicle signal at each wheel, an error correction value or weight is applied according to the vehicle state. control method.
The method of claim 7, wherein the step of controlling the in-wheel motor driving unit by adjusting the in-wheel escape speed includes:
The control unit comparing the main difference between each wheel and a second set value, and controlling the in-wheel motor driving unit by increasing the in-wheel escape speed when the difference is less than the second set value;
The control unit comparing the main difference between each wheel and the second set value and determining whether oversteer may occur if the difference is greater than the second set value; and
In-wheel motor driving of the in-wheel system, comprising the step of controlling the in-wheel motor driving unit by reducing the in-wheel escape speed when the control unit determines that oversteer is possible and determines that oversteer is possible. Device control method.
The method of claim 10, further comprising the step of controlling the in-wheel motor driving unit by increasing the in-wheel escape speed when the control unit determines that oversteer is possible and it is not determined that oversteer is possible. A method of controlling the in-wheel motor driving device of an in-wheel system.
The method of claim 10, wherein the second set value is set differently depending on the speed of the vehicle.

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